1. Field of the Invention
The present invention relates to a process for preparing crystalline zeolite ZSM-11 using a templating agent comprising at least one 3,5-dimethylpiperidinium (3,5-DMP) compound, and to zeolite ZSM-11 in pure phase form.
2. State of the Art
Zeolite ZSM-11 and methods for making it are known. For example, U.S. Pat. No. 3,709,979, issued Jan. 9, 1973 to Chu, discloses the preparation of ZSM-11 using quaternary cations of a Group 5-A element, such as ammonium and phosphonium compounds, as the organic templating agent. It does not, however, disclose the 3,5-DMP compounds of this invention as templating agents. U.S. Pat. No. 3,709,979 is incorporated herein by reference in its entirety.
U.S. Pat. No. 4,108,881, issued Aug. 22, 1978 to Rollman et al., teaches the synthesis of ZSM-11 using C.sub.7 -C.sub.12 alkylenediamines as the organic templating agent.
U.S. Pat. No. 4,894,212, issued Jan. 16, 1990 to McWilliams et al., discloses a method for synthesizing ZSM-11 using octylamine as the organic templating agent.
U.S. Pat. No. 4,941,963, issued Jul. 17, 1990 to Valyocsik, discloses a method for synthesizing ZSM-11 from a reaction mixture containing a diquaternary ammonium templating agent.
It is alleged that pure ZSM-11 has been synthesized using tetrabutylphosphonium, tetrabutylammonium and 1,8-diaminooctane (C.sub.8) and 1,9-diaminononane (C.sub.9). See P. A. Jacobs and J. A. Martens, Studies in Surface Science and Catalysis, 33, p. 147-166.
Lok et al., in Zeolites, 3, 282-291 (1983), disclose numerous compounds which act as templating agents for the synthesis of various crystalline materials, including ZSM-11. This article does not, however, disclose the organic templating agent of the present invention for the synthesis of ZSM-11.
U.S. Pat. No. 5,213,786, issued May 25, 1993 to Beck et al., discloses the synthesis of ZSM-11 using a trimethyl ammonium cation having the formula C.sub.n N.sup.+ (CH.sub.3).sub.3 where n is 9, 10, 11, or 12 as the organic templating agent. These trimethylammonium compounds are said to supply the proper pore-filling and charge density balance to produce ZSM-11 at the expense of ZSM-5.
It has now been found that ZSM-11 can be prepared using 3,5-DMP compounds as the templating agent and that the resulting ZSM-11 product is in pure phase form.